Commit Graph

4 Commits

Author SHA1 Message Date
Eric Fiselier f6e09e537b Update in-tree Google Benchmark to current ToT.
I've put some work into the Google Benchmark library in order to make it easier
to benchmark libc++. These changes have already been upstreamed into
Google Benchmark and this patch applies the changes to the in-tree version.

The main improvement in the addition of a 'compare_bench.py' script which
makes it very easy to compare benchmarks. For example to compare the native
STL to libc++ you would run:

`$ compare_bench.py ./util_smartptr.native.out ./util_smartptr.libcxx.out`

And the output would look like:

RUNNING: ./util_smartptr.native.out
Benchmark                          Time           CPU Iterations
----------------------------------------------------------------
BM_SharedPtrCreateDestroy         62 ns         62 ns   10937500
BM_SharedPtrIncDecRef             31 ns         31 ns   23972603
BM_WeakPtrIncDecRef               28 ns         28 ns   23648649
RUNNING: ./util_smartptr.libcxx.out
Benchmark                          Time           CPU Iterations
----------------------------------------------------------------
BM_SharedPtrCreateDestroy         46 ns         46 ns   14957265
BM_SharedPtrIncDecRef             31 ns         31 ns   22435897
BM_WeakPtrIncDecRef               34 ns         34 ns   21084337
Comparing ./util_smartptr.native.out to ./util_smartptr.libcxx.out
Benchmark                          Time           CPU
-----------------------------------------------------
BM_SharedPtrCreateDestroy         -0.26         -0.26
BM_SharedPtrIncDecRef             +0.00         +0.00
BM_WeakPtrIncDecRef               +0.21         +0.21

llvm-svn: 278147
2016-08-09 18:56:48 +00:00
Eric Fiselier 1a06fe5f7e Skip chash computation in insert/emplace if the unconstrained hash matches.
llvm-svn: 276549
2016-07-24 06:22:25 +00:00
Eric Fiselier b08d8b189c [libcxx] Add support for benchmark tests using Google Benchmark.
Summary:
This patch does the following:

1. Checks in a copy of the Google Benchmark library into the libc++ repo under `utils/google-benchmark`.
2. Teaches libc++ how to build Google Benchmark against both (A) in-tree libc++ and (B) the platforms native STL.
3. Allows performance benchmarks to be built as part of the libc++ build.

Building the benchmarks (and Google Benchmark) is off by default. It must be enabled using the CMake option `-DLIBCXX_INCLUDE_BENCHMARKS=ON`. When this option is enabled the tests under `libcxx/benchmarks`  can be built using the `libcxx-benchmarks` target.

On Linux platforms where libstdc++ is the default STL the CMake option `-DLIBCXX_BUILD_BENCHMARKS_NATIVE_STDLIB=ON` can be used to build each benchmark test against libstdc++ as well. This is useful for comparing performance between standard libraries.

Support for benchmarks is currently very minimal. They must be manually run by the user and there is no mechanism for detecting performance regressions.

Known Issues:

* `-DLIBCXX_INCLUDE_BENCHMARKS=ON` is only supported for Clang, and not GCC, since the `-stdlib=libc++` option is needed to build Google Benchmark.








Reviewers: danalbert, dberlin, chandlerc, mclow.lists, jroelofs

Subscribers: chandlerc, dberlin, tberghammer, danalbert, srhines, hfinkel

Differential Revision: https://reviews.llvm.org/D22240

llvm-svn: 276049
2016-07-19 23:07:03 +00:00
Eric Fiselier c835c12f6c Add unordered_map::insert benchmark test and rename file
llvm-svn: 274424
2016-07-02 05:30:54 +00:00